Pr = friisrxpow(lambda,R,Pt)
returns the received power Pr at a receiver located a distance
R away from a transmitter. Pt is the transmitted
power and lambda is the wavelength.
Pr = friisrxpow(lambda,R,Pt,name=value)
specifies additional options using one or more name-value arguments in addition to the input
arguments of the previous syntax.
Use the Friis equation to compute the received power at a receiver located 10 km away from a transmitter. The transmitted power is 0.5 W and the frequency is 437 MHz. The path loss exponent is 2.
Pt = 0.5;
f = 437*1e6;
lambda = physconst("LightSpeed")/f;
R = 10e3;
Pr = friisrxpow(lambda,R,Pt,"PathLossExponent",2)
Signal wavelength, specified as a positive scalar or a positive-valued
1-by-N row vector. If more than one input is a vector, the size
N must be the same for all inputs. Units are in meters.
Example: 3.0e8
Data Types: double
Distance to the radar receiver from the transmitter, specified as a positive scalar
or a positive-valued 1-by-N row vector. If more than one input is a
vector, the size N must be the same for all inputs. Units are in
meters.
Example: 1500
Data Types: double
Transmitted power, specified as a positive scalar or a positive-valued
1-by-N row vector. Units are in Watts.
Pt and R can be scalars or row vectors. If
both inputs are vectors, the size N must be the same for all
inputs.
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN, where Name is
the argument name and Value is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Example: PathLossExponent=2.5
Receive and transmit antenna gains, specified as a real-valued row vector or
real-valued 2-column matrix. Units are in dBi.
When Gain is a row vector, the transmit and receive
antennas have the same gain. The number of columns must either equal 1 or be
equal to the number of columns in Pt or
R if any one of them is a vector.
When Gain is a 2-row matrix, the first row specifies
the gain of the transmit antenna and the second row specifies the gain of the
receive antenna.
Example: Gain=[10,20]
Data Types: double
Additional system loss, specified as a row vector. System losses include
transmitter, receiver, or atmospheric losses. The number of columns in the
Loss property must either be 1 or match the number of columns
in the Pt and R input arguments or the
Gain if any one of them is a vector. Units are in dB.
Example: Loss=[5 10]
Data Types: double
Path loss exponent, specified as a real-valued row vector. The number of columns
must either equal 1 or match the number of columns in Pt,
R, or Gain. Units are
dimensionless.
Received power, returned as a positive-valued row vector. The received power is
computed from the corresponding lambda, Pt,
and R pairs. Units are in Watts.
